diff --git a/sys/compat/linuxkpi/common/src/linux_compat.c b/sys/compat/linuxkpi/common/src/linux_compat.c
index 707c5e47512e..5f7e2664bee1 100644
--- a/sys/compat/linuxkpi/common/src/linux_compat.c
+++ b/sys/compat/linuxkpi/common/src/linux_compat.c
@@ -1,2567 +1,2573 @@
 /*-
  * Copyright (c) 2010 Isilon Systems, Inc.
  * Copyright (c) 2010 iX Systems, Inc.
  * Copyright (c) 2010 Panasas, Inc.
  * Copyright (c) 2013-2018 Mellanox Technologies, Ltd.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice unmodified, this list of conditions, and the following
  *    disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include "opt_stack.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/malloc.h>
 #include <sys/kernel.h>
 #include <sys/sysctl.h>
 #include <sys/proc.h>
 #include <sys/sglist.h>
 #include <sys/sleepqueue.h>
 #include <sys/refcount.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/bus.h>
 #include <sys/eventhandler.h>
 #include <sys/fcntl.h>
 #include <sys/file.h>
 #include <sys/filio.h>
 #include <sys/rwlock.h>
 #include <sys/mman.h>
 #include <sys/stack.h>
 #include <sys/user.h>
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
 #include <vm/vm_object.h>
 #include <vm/vm_page.h>
 #include <vm/vm_pager.h>
 
 #include <machine/stdarg.h>
 
 #if defined(__i386__) || defined(__amd64__)
 #include <machine/md_var.h>
 #endif
 
 #include <linux/kobject.h>
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/cdev.h>
 #include <linux/file.h>
 #include <linux/sysfs.h>
 #include <linux/mm.h>
 #include <linux/io.h>
 #include <linux/vmalloc.h>
 #include <linux/netdevice.h>
 #include <linux/timer.h>
 #include <linux/interrupt.h>
 #include <linux/uaccess.h>
 #include <linux/list.h>
 #include <linux/kthread.h>
 #include <linux/kernel.h>
 #include <linux/compat.h>
 #include <linux/poll.h>
 #include <linux/smp.h>
 #include <linux/wait_bit.h>
 
 #if defined(__i386__) || defined(__amd64__)
 #include <asm/smp.h>
 #endif
 
 SYSCTL_NODE(_compat, OID_AUTO, linuxkpi, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
     "LinuxKPI parameters");
 
 int linuxkpi_debug;
 SYSCTL_INT(_compat_linuxkpi, OID_AUTO, debug, CTLFLAG_RWTUN,
     &linuxkpi_debug, 0, "Set to enable pr_debug() prints. Clear to disable.");
 
 MALLOC_DEFINE(M_KMALLOC, "linux", "Linux kmalloc compat");
 
 #include <linux/rbtree.h>
 /* Undo Linux compat changes. */
 #undef RB_ROOT
 #undef file
 #undef cdev
 #define	RB_ROOT(head)	(head)->rbh_root
 
 static void linux_cdev_deref(struct linux_cdev *ldev);
 static struct vm_area_struct *linux_cdev_handle_find(void *handle);
 
 struct kobject linux_class_root;
 struct device linux_root_device;
 struct class linux_class_misc;
 struct list_head pci_drivers;
 struct list_head pci_devices;
 spinlock_t pci_lock;
 
 unsigned long linux_timer_hz_mask;
 
 wait_queue_head_t linux_bit_waitq;
 wait_queue_head_t linux_var_waitq;
 
 int
 panic_cmp(struct rb_node *one, struct rb_node *two)
 {
 	panic("no cmp");
 }
 
 RB_GENERATE(linux_root, rb_node, __entry, panic_cmp);
 
 int
 kobject_set_name_vargs(struct kobject *kobj, const char *fmt, va_list args)
 {
 	va_list tmp_va;
 	int len;
 	char *old;
 	char *name;
 	char dummy;
 
 	old = kobj->name;
 
 	if (old && fmt == NULL)
 		return (0);
 
 	/* compute length of string */
 	va_copy(tmp_va, args);
 	len = vsnprintf(&dummy, 0, fmt, tmp_va);
 	va_end(tmp_va);
 
 	/* account for zero termination */
 	len++;
 
 	/* check for error */
 	if (len < 1)
 		return (-EINVAL);
 
 	/* allocate memory for string */
 	name = kzalloc(len, GFP_KERNEL);
 	if (name == NULL)
 		return (-ENOMEM);
 	vsnprintf(name, len, fmt, args);
 	kobj->name = name;
 
 	/* free old string */
 	kfree(old);
 
 	/* filter new string */
 	for (; *name != '\0'; name++)
 		if (*name == '/')
 			*name = '!';
 	return (0);
 }
 
 int
 kobject_set_name(struct kobject *kobj, const char *fmt, ...)
 {
 	va_list args;
 	int error;
 
 	va_start(args, fmt);
 	error = kobject_set_name_vargs(kobj, fmt, args);
 	va_end(args);
 
 	return (error);
 }
 
 static int
 kobject_add_complete(struct kobject *kobj, struct kobject *parent)
 {
 	const struct kobj_type *t;
 	int error;
 
 	kobj->parent = parent;
 	error = sysfs_create_dir(kobj);
 	if (error == 0 && kobj->ktype && kobj->ktype->default_attrs) {
 		struct attribute **attr;
 		t = kobj->ktype;
 
 		for (attr = t->default_attrs; *attr != NULL; attr++) {
 			error = sysfs_create_file(kobj, *attr);
 			if (error)
 				break;
 		}
 		if (error)
 			sysfs_remove_dir(kobj);
 	}
 	return (error);
 }
 
 int
 kobject_add(struct kobject *kobj, struct kobject *parent, const char *fmt, ...)
 {
 	va_list args;
 	int error;
 
 	va_start(args, fmt);
 	error = kobject_set_name_vargs(kobj, fmt, args);
 	va_end(args);
 	if (error)
 		return (error);
 
 	return kobject_add_complete(kobj, parent);
 }
 
 void
 linux_kobject_release(struct kref *kref)
 {
 	struct kobject *kobj;
 	char *name;
 
 	kobj = container_of(kref, struct kobject, kref);
 	sysfs_remove_dir(kobj);
 	name = kobj->name;
 	if (kobj->ktype && kobj->ktype->release)
 		kobj->ktype->release(kobj);
 	kfree(name);
 }
 
 static void
 linux_kobject_kfree(struct kobject *kobj)
 {
 	kfree(kobj);
 }
 
 static void
 linux_kobject_kfree_name(struct kobject *kobj)
 {
 	if (kobj) {
 		kfree(kobj->name);
 	}
 }
 
 const struct kobj_type linux_kfree_type = {
 	.release = linux_kobject_kfree
 };
 
 static void
 linux_device_release(struct device *dev)
 {
 	pr_debug("linux_device_release: %s\n", dev_name(dev));
 	kfree(dev);
 }
 
 static ssize_t
 linux_class_show(struct kobject *kobj, struct attribute *attr, char *buf)
 {
 	struct class_attribute *dattr;
 	ssize_t error;
 
 	dattr = container_of(attr, struct class_attribute, attr);
 	error = -EIO;
 	if (dattr->show)
 		error = dattr->show(container_of(kobj, struct class, kobj),
 		    dattr, buf);
 	return (error);
 }
 
 static ssize_t
 linux_class_store(struct kobject *kobj, struct attribute *attr, const char *buf,
     size_t count)
 {
 	struct class_attribute *dattr;
 	ssize_t error;
 
 	dattr = container_of(attr, struct class_attribute, attr);
 	error = -EIO;
 	if (dattr->store)
 		error = dattr->store(container_of(kobj, struct class, kobj),
 		    dattr, buf, count);
 	return (error);
 }
 
 static void
 linux_class_release(struct kobject *kobj)
 {
 	struct class *class;
 
 	class = container_of(kobj, struct class, kobj);
 	if (class->class_release)
 		class->class_release(class);
 }
 
 static const struct sysfs_ops linux_class_sysfs = {
 	.show  = linux_class_show,
 	.store = linux_class_store,
 };
 
 const struct kobj_type linux_class_ktype = {
 	.release = linux_class_release,
 	.sysfs_ops = &linux_class_sysfs
 };
 
 static void
 linux_dev_release(struct kobject *kobj)
 {
 	struct device *dev;
 
 	dev = container_of(kobj, struct device, kobj);
 	/* This is the precedence defined by linux. */
 	if (dev->release)
 		dev->release(dev);
 	else if (dev->class && dev->class->dev_release)
 		dev->class->dev_release(dev);
 }
 
 static ssize_t
 linux_dev_show(struct kobject *kobj, struct attribute *attr, char *buf)
 {
 	struct device_attribute *dattr;
 	ssize_t error;
 
 	dattr = container_of(attr, struct device_attribute, attr);
 	error = -EIO;
 	if (dattr->show)
 		error = dattr->show(container_of(kobj, struct device, kobj),
 		    dattr, buf);
 	return (error);
 }
 
 static ssize_t
 linux_dev_store(struct kobject *kobj, struct attribute *attr, const char *buf,
     size_t count)
 {
 	struct device_attribute *dattr;
 	ssize_t error;
 
 	dattr = container_of(attr, struct device_attribute, attr);
 	error = -EIO;
 	if (dattr->store)
 		error = dattr->store(container_of(kobj, struct device, kobj),
 		    dattr, buf, count);
 	return (error);
 }
 
 static const struct sysfs_ops linux_dev_sysfs = {
 	.show  = linux_dev_show,
 	.store = linux_dev_store,
 };
 
 const struct kobj_type linux_dev_ktype = {
 	.release = linux_dev_release,
 	.sysfs_ops = &linux_dev_sysfs
 };
 
 struct device *
 device_create(struct class *class, struct device *parent, dev_t devt,
     void *drvdata, const char *fmt, ...)
 {
 	struct device *dev;
 	va_list args;
 
 	dev = kzalloc(sizeof(*dev), M_WAITOK);
 	dev->parent = parent;
 	dev->class = class;
 	dev->devt = devt;
 	dev->driver_data = drvdata;
 	dev->release = linux_device_release;
 	va_start(args, fmt);
 	kobject_set_name_vargs(&dev->kobj, fmt, args);
 	va_end(args);
 	device_register(dev);
 
 	return (dev);
 }
 
 int
 kobject_init_and_add(struct kobject *kobj, const struct kobj_type *ktype,
     struct kobject *parent, const char *fmt, ...)
 {
 	va_list args;
 	int error;
 
 	kobject_init(kobj, ktype);
 	kobj->ktype = ktype;
 	kobj->parent = parent;
 	kobj->name = NULL;
 
 	va_start(args, fmt);
 	error = kobject_set_name_vargs(kobj, fmt, args);
 	va_end(args);
 	if (error)
 		return (error);
 	return kobject_add_complete(kobj, parent);
 }
 
 static void
 linux_kq_lock(void *arg)
 {
 	spinlock_t *s = arg;
 
 	spin_lock(s);
 }
 static void
 linux_kq_unlock(void *arg)
 {
 	spinlock_t *s = arg;
 
 	spin_unlock(s);
 }
 
 static void
 linux_kq_assert_lock(void *arg, int what)
 {
 #ifdef INVARIANTS
 	spinlock_t *s = arg;
 
 	if (what == LA_LOCKED)
 		mtx_assert(&s->m, MA_OWNED);
 	else
 		mtx_assert(&s->m, MA_NOTOWNED);
 #endif
 }
 
 static void
 linux_file_kqfilter_poll(struct linux_file *, int);
 
 struct linux_file *
 linux_file_alloc(void)
 {
 	struct linux_file *filp;
 
 	filp = kzalloc(sizeof(*filp), GFP_KERNEL);
 
 	/* set initial refcount */
 	filp->f_count = 1;
 
 	/* setup fields needed by kqueue support */
 	spin_lock_init(&filp->f_kqlock);
 	knlist_init(&filp->f_selinfo.si_note, &filp->f_kqlock,
 	    linux_kq_lock, linux_kq_unlock, linux_kq_assert_lock);
 
 	return (filp);
 }
 
 void
 linux_file_free(struct linux_file *filp)
 {
 	if (filp->_file == NULL) {
 		if (filp->f_shmem != NULL)
 			vm_object_deallocate(filp->f_shmem);
 		kfree(filp);
 	} else {
 		/*
 		 * The close method of the character device or file
 		 * will free the linux_file structure:
 		 */
 		_fdrop(filp->_file, curthread);
 	}
 }
 
 static int
 linux_cdev_pager_fault(vm_object_t vm_obj, vm_ooffset_t offset, int prot,
     vm_page_t *mres)
 {
 	struct vm_area_struct *vmap;
 
 	vmap = linux_cdev_handle_find(vm_obj->handle);
 
 	MPASS(vmap != NULL);
 	MPASS(vmap->vm_private_data == vm_obj->handle);
 
 	if (likely(vmap->vm_ops != NULL && offset < vmap->vm_len)) {
 		vm_paddr_t paddr = IDX_TO_OFF(vmap->vm_pfn) + offset;
 		vm_page_t page;
 
 		if (((*mres)->flags & PG_FICTITIOUS) != 0) {
 			/*
 			 * If the passed in result page is a fake
 			 * page, update it with the new physical
 			 * address.
 			 */
 			page = *mres;
 			vm_page_updatefake(page, paddr, vm_obj->memattr);
 		} else {
 			/*
 			 * Replace the passed in "mres" page with our
 			 * own fake page and free up the all of the
 			 * original pages.
 			 */
 			VM_OBJECT_WUNLOCK(vm_obj);
 			page = vm_page_getfake(paddr, vm_obj->memattr);
 			VM_OBJECT_WLOCK(vm_obj);
 
 			vm_page_replace(page, vm_obj, (*mres)->pindex, *mres);
 			*mres = page;
 		}
 		vm_page_valid(page);
 		return (VM_PAGER_OK);
 	}
 	return (VM_PAGER_FAIL);
 }
 
 static int
 linux_cdev_pager_populate(vm_object_t vm_obj, vm_pindex_t pidx, int fault_type,
     vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last)
 {
 	struct vm_area_struct *vmap;
 	int err;
 
 	/* get VM area structure */
 	vmap = linux_cdev_handle_find(vm_obj->handle);
 	MPASS(vmap != NULL);
 	MPASS(vmap->vm_private_data == vm_obj->handle);
 
 	VM_OBJECT_WUNLOCK(vm_obj);
 
 	linux_set_current(curthread);
 
 	down_write(&vmap->vm_mm->mmap_sem);
 	if (unlikely(vmap->vm_ops == NULL)) {
 		err = VM_FAULT_SIGBUS;
 	} else {
 		struct vm_fault vmf;
 
 		/* fill out VM fault structure */
 		vmf.virtual_address = (void *)(uintptr_t)IDX_TO_OFF(pidx);
 		vmf.flags = (fault_type & VM_PROT_WRITE) ? FAULT_FLAG_WRITE : 0;
 		vmf.pgoff = 0;
 		vmf.page = NULL;
 		vmf.vma = vmap;
 
 		vmap->vm_pfn_count = 0;
 		vmap->vm_pfn_pcount = &vmap->vm_pfn_count;
 		vmap->vm_obj = vm_obj;
 
 		err = vmap->vm_ops->fault(vmap, &vmf);
 
 		while (vmap->vm_pfn_count == 0 && err == VM_FAULT_NOPAGE) {
 			kern_yield(PRI_USER);
 			err = vmap->vm_ops->fault(vmap, &vmf);
 		}
 	}
 
 	/* translate return code */
 	switch (err) {
 	case VM_FAULT_OOM:
 		err = VM_PAGER_AGAIN;
 		break;
 	case VM_FAULT_SIGBUS:
 		err = VM_PAGER_BAD;
 		break;
 	case VM_FAULT_NOPAGE:
 		/*
 		 * By contract the fault handler will return having
 		 * busied all the pages itself. If pidx is already
 		 * found in the object, it will simply xbusy the first
 		 * page and return with vm_pfn_count set to 1.
 		 */
 		*first = vmap->vm_pfn_first;
 		*last = *first + vmap->vm_pfn_count - 1;
 		err = VM_PAGER_OK;
 		break;
 	default:
 		err = VM_PAGER_ERROR;
 		break;
 	}
 	up_write(&vmap->vm_mm->mmap_sem);
 	VM_OBJECT_WLOCK(vm_obj);
 	return (err);
 }
 
 static struct rwlock linux_vma_lock;
 static TAILQ_HEAD(, vm_area_struct) linux_vma_head =
     TAILQ_HEAD_INITIALIZER(linux_vma_head);
 
 static void
 linux_cdev_handle_free(struct vm_area_struct *vmap)
 {
 	/* Drop reference on vm_file */
 	if (vmap->vm_file != NULL)
 		fput(vmap->vm_file);
 
 	/* Drop reference on mm_struct */
 	mmput(vmap->vm_mm);
 
 	kfree(vmap);
 }
 
 static void
 linux_cdev_handle_remove(struct vm_area_struct *vmap)
 {
 	rw_wlock(&linux_vma_lock);
 	TAILQ_REMOVE(&linux_vma_head, vmap, vm_entry);
 	rw_wunlock(&linux_vma_lock);
 }
 
 static struct vm_area_struct *
 linux_cdev_handle_find(void *handle)
 {
 	struct vm_area_struct *vmap;
 
 	rw_rlock(&linux_vma_lock);
 	TAILQ_FOREACH(vmap, &linux_vma_head, vm_entry) {
 		if (vmap->vm_private_data == handle)
 			break;
 	}
 	rw_runlock(&linux_vma_lock);
 	return (vmap);
 }
 
 static int
 linux_cdev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
 		      vm_ooffset_t foff, struct ucred *cred, u_short *color)
 {
 
 	MPASS(linux_cdev_handle_find(handle) != NULL);
 	*color = 0;
 	return (0);
 }
 
 static void
 linux_cdev_pager_dtor(void *handle)
 {
 	const struct vm_operations_struct *vm_ops;
 	struct vm_area_struct *vmap;
 
 	vmap = linux_cdev_handle_find(handle);
 	MPASS(vmap != NULL);
 
 	/*
 	 * Remove handle before calling close operation to prevent
 	 * other threads from reusing the handle pointer.
 	 */
 	linux_cdev_handle_remove(vmap);
 
 	down_write(&vmap->vm_mm->mmap_sem);
 	vm_ops = vmap->vm_ops;
 	if (likely(vm_ops != NULL))
 		vm_ops->close(vmap);
 	up_write(&vmap->vm_mm->mmap_sem);
 
 	linux_cdev_handle_free(vmap);
 }
 
 static struct cdev_pager_ops linux_cdev_pager_ops[2] = {
   {
 	/* OBJT_MGTDEVICE */
 	.cdev_pg_populate	= linux_cdev_pager_populate,
 	.cdev_pg_ctor	= linux_cdev_pager_ctor,
 	.cdev_pg_dtor	= linux_cdev_pager_dtor
   },
   {
 	/* OBJT_DEVICE */
 	.cdev_pg_fault	= linux_cdev_pager_fault,
 	.cdev_pg_ctor	= linux_cdev_pager_ctor,
 	.cdev_pg_dtor	= linux_cdev_pager_dtor
   },
 };
 
 int
 zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
     unsigned long size)
 {
 	vm_object_t obj;
 	vm_page_t m;
 
 	obj = vma->vm_obj;
 	if (obj == NULL || (obj->flags & OBJ_UNMANAGED) != 0)
 		return (-ENOTSUP);
 	VM_OBJECT_RLOCK(obj);
 	for (m = vm_page_find_least(obj, OFF_TO_IDX(address));
 	    m != NULL && m->pindex < OFF_TO_IDX(address + size);
 	    m = TAILQ_NEXT(m, listq))
 		pmap_remove_all(m);
 	VM_OBJECT_RUNLOCK(obj);
 	return (0);
 }
 
 static struct file_operations dummy_ldev_ops = {
 	/* XXXKIB */
 };
 
 static struct linux_cdev dummy_ldev = {
 	.ops = &dummy_ldev_ops,
 };
 
 #define	LDEV_SI_DTR	0x0001
 #define	LDEV_SI_REF	0x0002
 
 static void
 linux_get_fop(struct linux_file *filp, const struct file_operations **fop,
     struct linux_cdev **dev)
 {
 	struct linux_cdev *ldev;
 	u_int siref;
 
 	ldev = filp->f_cdev;
 	*fop = filp->f_op;
 	if (ldev != NULL) {
 		for (siref = ldev->siref;;) {
 			if ((siref & LDEV_SI_DTR) != 0) {
 				ldev = &dummy_ldev;
 				siref = ldev->siref;
 				*fop = ldev->ops;
 				MPASS((ldev->siref & LDEV_SI_DTR) == 0);
 			} else if (atomic_fcmpset_int(&ldev->siref, &siref,
 			    siref + LDEV_SI_REF)) {
 				break;
 			}
 		}
 	}
 	*dev = ldev;
 }
 
 static void
 linux_drop_fop(struct linux_cdev *ldev)
 {
 
 	if (ldev == NULL)
 		return;
 	MPASS((ldev->siref & ~LDEV_SI_DTR) != 0);
 	atomic_subtract_int(&ldev->siref, LDEV_SI_REF);
 }
 
 #define	OPW(fp,td,code) ({			\
 	struct file *__fpop;			\
 	__typeof(code) __retval;		\
 						\
 	__fpop = (td)->td_fpop;			\
 	(td)->td_fpop = (fp);			\
 	__retval = (code);			\
 	(td)->td_fpop = __fpop;			\
 	__retval;				\
 })
 
 static int
 linux_dev_fdopen(struct cdev *dev, int fflags, struct thread *td,
     struct file *file)
 {
 	struct linux_cdev *ldev;
 	struct linux_file *filp;
 	const struct file_operations *fop;
 	int error;
 
 	ldev = dev->si_drv1;
 
 	filp = linux_file_alloc();
 	filp->f_dentry = &filp->f_dentry_store;
 	filp->f_op = ldev->ops;
 	filp->f_mode = file->f_flag;
 	filp->f_flags = file->f_flag;
 	filp->f_vnode = file->f_vnode;
 	filp->_file = file;
 	refcount_acquire(&ldev->refs);
 	filp->f_cdev = ldev;
 
 	linux_set_current(td);
 	linux_get_fop(filp, &fop, &ldev);
 
 	if (fop->open != NULL) {
 		error = -fop->open(file->f_vnode, filp);
 		if (error != 0) {
 			linux_drop_fop(ldev);
 			linux_cdev_deref(filp->f_cdev);
 			kfree(filp);
 			return (error);
 		}
 	}
 
 	/* hold on to the vnode - used for fstat() */
 	vhold(filp->f_vnode);
 
 	/* release the file from devfs */
 	finit(file, filp->f_mode, DTYPE_DEV, filp, &linuxfileops);
 	linux_drop_fop(ldev);
 	return (ENXIO);
 }
 
 #define	LINUX_IOCTL_MIN_PTR 0x10000UL
 #define	LINUX_IOCTL_MAX_PTR (LINUX_IOCTL_MIN_PTR + IOCPARM_MAX)
 
 static inline int
 linux_remap_address(void **uaddr, size_t len)
 {
 	uintptr_t uaddr_val = (uintptr_t)(*uaddr);
 
 	if (unlikely(uaddr_val >= LINUX_IOCTL_MIN_PTR &&
 	    uaddr_val < LINUX_IOCTL_MAX_PTR)) {
 		struct task_struct *pts = current;
 		if (pts == NULL) {
 			*uaddr = NULL;
 			return (1);
 		}
 
 		/* compute data offset */
 		uaddr_val -= LINUX_IOCTL_MIN_PTR;
 
 		/* check that length is within bounds */
 		if ((len > IOCPARM_MAX) ||
 		    (uaddr_val + len) > pts->bsd_ioctl_len) {
 			*uaddr = NULL;
 			return (1);
 		}
 
 		/* re-add kernel buffer address */
 		uaddr_val += (uintptr_t)pts->bsd_ioctl_data;
 
 		/* update address location */
 		*uaddr = (void *)uaddr_val;
 		return (1);
 	}
 	return (0);
 }
 
 int
 linux_copyin(const void *uaddr, void *kaddr, size_t len)
 {
 	if (linux_remap_address(__DECONST(void **, &uaddr), len)) {
 		if (uaddr == NULL)
 			return (-EFAULT);
 		memcpy(kaddr, uaddr, len);
 		return (0);
 	}
 	return (-copyin(uaddr, kaddr, len));
 }
 
 int
 linux_copyout(const void *kaddr, void *uaddr, size_t len)
 {
 	if (linux_remap_address(&uaddr, len)) {
 		if (uaddr == NULL)
 			return (-EFAULT);
 		memcpy(uaddr, kaddr, len);
 		return (0);
 	}
 	return (-copyout(kaddr, uaddr, len));
 }
 
 size_t
 linux_clear_user(void *_uaddr, size_t _len)
 {
 	uint8_t *uaddr = _uaddr;
 	size_t len = _len;
 
 	/* make sure uaddr is aligned before going into the fast loop */
 	while (((uintptr_t)uaddr & 7) != 0 && len > 7) {
 		if (subyte(uaddr, 0))
 			return (_len);
 		uaddr++;
 		len--;
 	}
 
 	/* zero 8 bytes at a time */
 	while (len > 7) {
 #ifdef __LP64__
 		if (suword64(uaddr, 0))
 			return (_len);
 #else
 		if (suword32(uaddr, 0))
 			return (_len);
 		if (suword32(uaddr + 4, 0))
 			return (_len);
 #endif
 		uaddr += 8;
 		len -= 8;
 	}
 
 	/* zero fill end, if any */
 	while (len > 0) {
 		if (subyte(uaddr, 0))
 			return (_len);
 		uaddr++;
 		len--;
 	}
 	return (0);
 }
 
 int
 linux_access_ok(const void *uaddr, size_t len)
 {
 	uintptr_t saddr;
 	uintptr_t eaddr;
 
 	/* get start and end address */
 	saddr = (uintptr_t)uaddr;
 	eaddr = (uintptr_t)uaddr + len;
 
 	/* verify addresses are valid for userspace */
 	return ((saddr == eaddr) ||
 	    (eaddr > saddr && eaddr <= VM_MAXUSER_ADDRESS));
 }
 
 /*
  * This function should return either EINTR or ERESTART depending on
  * the signal type sent to this thread:
  */
 static int
 linux_get_error(struct task_struct *task, int error)
 {
 	/* check for signal type interrupt code */
 	if (error == EINTR || error == ERESTARTSYS || error == ERESTART) {
 		error = -linux_schedule_get_interrupt_value(task);
 		if (error == 0)
 			error = EINTR;
 	}
 	return (error);
 }
 
 static int
 linux_file_ioctl_sub(struct file *fp, struct linux_file *filp,
     const struct file_operations *fop, u_long cmd, caddr_t data,
     struct thread *td)
 {
 	struct task_struct *task = current;
 	unsigned size;
 	int error;
 
 	size = IOCPARM_LEN(cmd);
 	/* refer to logic in sys_ioctl() */
 	if (size > 0) {
 		/*
 		 * Setup hint for linux_copyin() and linux_copyout().
 		 *
 		 * Background: Linux code expects a user-space address
 		 * while FreeBSD supplies a kernel-space address.
 		 */
 		task->bsd_ioctl_data = data;
 		task->bsd_ioctl_len = size;
 		data = (void *)LINUX_IOCTL_MIN_PTR;
 	} else {
 		/* fetch user-space pointer */
 		data = *(void **)data;
 	}
 #if defined(__amd64__)
 	if (td->td_proc->p_elf_machine == EM_386) {
 		/* try the compat IOCTL handler first */
 		if (fop->compat_ioctl != NULL) {
 			error = -OPW(fp, td, fop->compat_ioctl(filp,
 			    cmd, (u_long)data));
 		} else {
 			error = ENOTTY;
 		}
 
 		/* fallback to the regular IOCTL handler, if any */
 		if (error == ENOTTY && fop->unlocked_ioctl != NULL) {
 			error = -OPW(fp, td, fop->unlocked_ioctl(filp,
 			    cmd, (u_long)data));
 		}
 	} else
 #endif
 	{
 		if (fop->unlocked_ioctl != NULL) {
 			error = -OPW(fp, td, fop->unlocked_ioctl(filp,
 			    cmd, (u_long)data));
 		} else {
 			error = ENOTTY;
 		}
 	}
 	if (size > 0) {
 		task->bsd_ioctl_data = NULL;
 		task->bsd_ioctl_len = 0;
 	}
 
 	if (error == EWOULDBLOCK) {
 		/* update kqfilter status, if any */
 		linux_file_kqfilter_poll(filp,
 		    LINUX_KQ_FLAG_HAS_READ | LINUX_KQ_FLAG_HAS_WRITE);
 	} else {
 		error = linux_get_error(task, error);
 	}
 	return (error);
 }
 
 #define	LINUX_POLL_TABLE_NORMAL ((poll_table *)1)
 
 /*
  * This function atomically updates the poll wakeup state and returns
  * the previous state at the time of update.
  */
 static uint8_t
 linux_poll_wakeup_state(atomic_t *v, const uint8_t *pstate)
 {
 	int c, old;
 
 	c = v->counter;
 
 	while ((old = atomic_cmpxchg(v, c, pstate[c])) != c)
 		c = old;
 
 	return (c);
 }
 
 static int
 linux_poll_wakeup_callback(wait_queue_t *wq, unsigned int wq_state, int flags, void *key)
 {
 	static const uint8_t state[LINUX_FWQ_STATE_MAX] = {
 		[LINUX_FWQ_STATE_INIT] = LINUX_FWQ_STATE_INIT, /* NOP */
 		[LINUX_FWQ_STATE_NOT_READY] = LINUX_FWQ_STATE_NOT_READY, /* NOP */
 		[LINUX_FWQ_STATE_QUEUED] = LINUX_FWQ_STATE_READY,
 		[LINUX_FWQ_STATE_READY] = LINUX_FWQ_STATE_READY, /* NOP */
 	};
 	struct linux_file *filp = container_of(wq, struct linux_file, f_wait_queue.wq);
 
 	switch (linux_poll_wakeup_state(&filp->f_wait_queue.state, state)) {
 	case LINUX_FWQ_STATE_QUEUED:
 		linux_poll_wakeup(filp);
 		return (1);
 	default:
 		return (0);
 	}
 }
 
 void
 linux_poll_wait(struct linux_file *filp, wait_queue_head_t *wqh, poll_table *p)
 {
 	static const uint8_t state[LINUX_FWQ_STATE_MAX] = {
 		[LINUX_FWQ_STATE_INIT] = LINUX_FWQ_STATE_NOT_READY,
 		[LINUX_FWQ_STATE_NOT_READY] = LINUX_FWQ_STATE_NOT_READY, /* NOP */
 		[LINUX_FWQ_STATE_QUEUED] = LINUX_FWQ_STATE_QUEUED, /* NOP */
 		[LINUX_FWQ_STATE_READY] = LINUX_FWQ_STATE_QUEUED,
 	};
 
 	/* check if we are called inside the select system call */
 	if (p == LINUX_POLL_TABLE_NORMAL)
 		selrecord(curthread, &filp->f_selinfo);
 
 	switch (linux_poll_wakeup_state(&filp->f_wait_queue.state, state)) {
 	case LINUX_FWQ_STATE_INIT:
 		/* NOTE: file handles can only belong to one wait-queue */
 		filp->f_wait_queue.wqh = wqh;
 		filp->f_wait_queue.wq.func = &linux_poll_wakeup_callback;
 		add_wait_queue(wqh, &filp->f_wait_queue.wq);
 		atomic_set(&filp->f_wait_queue.state, LINUX_FWQ_STATE_QUEUED);
 		break;
 	default:
 		break;
 	}
 }
 
 static void
 linux_poll_wait_dequeue(struct linux_file *filp)
 {
 	static const uint8_t state[LINUX_FWQ_STATE_MAX] = {
 		[LINUX_FWQ_STATE_INIT] = LINUX_FWQ_STATE_INIT,	/* NOP */
 		[LINUX_FWQ_STATE_NOT_READY] = LINUX_FWQ_STATE_INIT,
 		[LINUX_FWQ_STATE_QUEUED] = LINUX_FWQ_STATE_INIT,
 		[LINUX_FWQ_STATE_READY] = LINUX_FWQ_STATE_INIT,
 	};
 
 	seldrain(&filp->f_selinfo);
 
 	switch (linux_poll_wakeup_state(&filp->f_wait_queue.state, state)) {
 	case LINUX_FWQ_STATE_NOT_READY:
 	case LINUX_FWQ_STATE_QUEUED:
 	case LINUX_FWQ_STATE_READY:
 		remove_wait_queue(filp->f_wait_queue.wqh, &filp->f_wait_queue.wq);
 		break;
 	default:
 		break;
 	}
 }
 
 void
 linux_poll_wakeup(struct linux_file *filp)
 {
 	/* this function should be NULL-safe */
 	if (filp == NULL)
 		return;
 
 	selwakeup(&filp->f_selinfo);
 
 	spin_lock(&filp->f_kqlock);
 	filp->f_kqflags |= LINUX_KQ_FLAG_NEED_READ |
 	    LINUX_KQ_FLAG_NEED_WRITE;
 
 	/* make sure the "knote" gets woken up */
 	KNOTE_LOCKED(&filp->f_selinfo.si_note, 1);
 	spin_unlock(&filp->f_kqlock);
 }
 
 static void
 linux_file_kqfilter_detach(struct knote *kn)
 {
 	struct linux_file *filp = kn->kn_hook;
 
 	spin_lock(&filp->f_kqlock);
 	knlist_remove(&filp->f_selinfo.si_note, kn, 1);
 	spin_unlock(&filp->f_kqlock);
 }
 
 static int
 linux_file_kqfilter_read_event(struct knote *kn, long hint)
 {
 	struct linux_file *filp = kn->kn_hook;
 
 	mtx_assert(&filp->f_kqlock.m, MA_OWNED);
 
 	return ((filp->f_kqflags & LINUX_KQ_FLAG_NEED_READ) ? 1 : 0);
 }
 
 static int
 linux_file_kqfilter_write_event(struct knote *kn, long hint)
 {
 	struct linux_file *filp = kn->kn_hook;
 
 	mtx_assert(&filp->f_kqlock.m, MA_OWNED);
 
 	return ((filp->f_kqflags & LINUX_KQ_FLAG_NEED_WRITE) ? 1 : 0);
 }
 
 static struct filterops linux_dev_kqfiltops_read = {
 	.f_isfd = 1,
 	.f_detach = linux_file_kqfilter_detach,
 	.f_event = linux_file_kqfilter_read_event,
 };
 
 static struct filterops linux_dev_kqfiltops_write = {
 	.f_isfd = 1,
 	.f_detach = linux_file_kqfilter_detach,
 	.f_event = linux_file_kqfilter_write_event,
 };
 
 static void
 linux_file_kqfilter_poll(struct linux_file *filp, int kqflags)
 {
 	struct thread *td;
 	const struct file_operations *fop;
 	struct linux_cdev *ldev;
 	int temp;
 
 	if ((filp->f_kqflags & kqflags) == 0)
 		return;
 
 	td = curthread;
 
 	linux_get_fop(filp, &fop, &ldev);
 	/* get the latest polling state */
 	temp = OPW(filp->_file, td, fop->poll(filp, NULL));
 	linux_drop_fop(ldev);
 
 	spin_lock(&filp->f_kqlock);
 	/* clear kqflags */
 	filp->f_kqflags &= ~(LINUX_KQ_FLAG_NEED_READ |
 	    LINUX_KQ_FLAG_NEED_WRITE);
 	/* update kqflags */
 	if ((temp & (POLLIN | POLLOUT)) != 0) {
 		if ((temp & POLLIN) != 0)
 			filp->f_kqflags |= LINUX_KQ_FLAG_NEED_READ;
 		if ((temp & POLLOUT) != 0)
 			filp->f_kqflags |= LINUX_KQ_FLAG_NEED_WRITE;
 
 		/* make sure the "knote" gets woken up */
 		KNOTE_LOCKED(&filp->f_selinfo.si_note, 0);
 	}
 	spin_unlock(&filp->f_kqlock);
 }
 
 static int
 linux_file_kqfilter(struct file *file, struct knote *kn)
 {
 	struct linux_file *filp;
 	struct thread *td;
 	int error;
 
 	td = curthread;
 	filp = (struct linux_file *)file->f_data;
 	filp->f_flags = file->f_flag;
 	if (filp->f_op->poll == NULL)
 		return (EINVAL);
 
 	spin_lock(&filp->f_kqlock);
 	switch (kn->kn_filter) {
 	case EVFILT_READ:
 		filp->f_kqflags |= LINUX_KQ_FLAG_HAS_READ;
 		kn->kn_fop = &linux_dev_kqfiltops_read;
 		kn->kn_hook = filp;
 		knlist_add(&filp->f_selinfo.si_note, kn, 1);
 		error = 0;
 		break;
 	case EVFILT_WRITE:
 		filp->f_kqflags |= LINUX_KQ_FLAG_HAS_WRITE;
 		kn->kn_fop = &linux_dev_kqfiltops_write;
 		kn->kn_hook = filp;
 		knlist_add(&filp->f_selinfo.si_note, kn, 1);
 		error = 0;
 		break;
 	default:
 		error = EINVAL;
 		break;
 	}
 	spin_unlock(&filp->f_kqlock);
 
 	if (error == 0) {
 		linux_set_current(td);
 
 		/* update kqfilter status, if any */
 		linux_file_kqfilter_poll(filp,
 		    LINUX_KQ_FLAG_HAS_READ | LINUX_KQ_FLAG_HAS_WRITE);
 	}
 	return (error);
 }
 
 static int
 linux_file_mmap_single(struct file *fp, const struct file_operations *fop,
     vm_ooffset_t *offset, vm_size_t size, struct vm_object **object,
     int nprot, struct thread *td)
 {
 	struct task_struct *task;
 	struct vm_area_struct *vmap;
 	struct mm_struct *mm;
 	struct linux_file *filp;
 	vm_memattr_t attr;
 	int error;
 
 	filp = (struct linux_file *)fp->f_data;
 	filp->f_flags = fp->f_flag;
 
 	if (fop->mmap == NULL)
 		return (EOPNOTSUPP);
 
 	linux_set_current(td);
 
 	/*
 	 * The same VM object might be shared by multiple processes
 	 * and the mm_struct is usually freed when a process exits.
 	 *
 	 * The atomic reference below makes sure the mm_struct is
 	 * available as long as the vmap is in the linux_vma_head.
 	 */
 	task = current;
 	mm = task->mm;
 	if (atomic_inc_not_zero(&mm->mm_users) == 0)
 		return (EINVAL);
 
 	vmap = kzalloc(sizeof(*vmap), GFP_KERNEL);
 	vmap->vm_start = 0;
 	vmap->vm_end = size;
 	vmap->vm_pgoff = *offset / PAGE_SIZE;
 	vmap->vm_pfn = 0;
 	vmap->vm_flags = vmap->vm_page_prot = (nprot & VM_PROT_ALL);
 	vmap->vm_ops = NULL;
 	vmap->vm_file = get_file(filp);
 	vmap->vm_mm = mm;
 
 	if (unlikely(down_write_killable(&vmap->vm_mm->mmap_sem))) {
 		error = linux_get_error(task, EINTR);
 	} else {
 		error = -OPW(fp, td, fop->mmap(filp, vmap));
 		error = linux_get_error(task, error);
 		up_write(&vmap->vm_mm->mmap_sem);
 	}
 
 	if (error != 0) {
 		linux_cdev_handle_free(vmap);
 		return (error);
 	}
 
 	attr = pgprot2cachemode(vmap->vm_page_prot);
 
 	if (vmap->vm_ops != NULL) {
 		struct vm_area_struct *ptr;
 		void *vm_private_data;
 		bool vm_no_fault;
 
 		if (vmap->vm_ops->open == NULL ||
 		    vmap->vm_ops->close == NULL ||
 		    vmap->vm_private_data == NULL) {
 			/* free allocated VM area struct */
 			linux_cdev_handle_free(vmap);
 			return (EINVAL);
 		}
 
 		vm_private_data = vmap->vm_private_data;
 
 		rw_wlock(&linux_vma_lock);
 		TAILQ_FOREACH(ptr, &linux_vma_head, vm_entry) {
 			if (ptr->vm_private_data == vm_private_data)
 				break;
 		}
 		/* check if there is an existing VM area struct */
 		if (ptr != NULL) {
 			/* check if the VM area structure is invalid */
 			if (ptr->vm_ops == NULL ||
 			    ptr->vm_ops->open == NULL ||
 			    ptr->vm_ops->close == NULL) {
 				error = ESTALE;
 				vm_no_fault = 1;
 			} else {
 				error = EEXIST;
 				vm_no_fault = (ptr->vm_ops->fault == NULL);
 			}
 		} else {
 			/* insert VM area structure into list */
 			TAILQ_INSERT_TAIL(&linux_vma_head, vmap, vm_entry);
 			error = 0;
 			vm_no_fault = (vmap->vm_ops->fault == NULL);
 		}
 		rw_wunlock(&linux_vma_lock);
 
 		if (error != 0) {
 			/* free allocated VM area struct */
 			linux_cdev_handle_free(vmap);
 			/* check for stale VM area struct */
 			if (error != EEXIST)
 				return (error);
 		}
 
 		/* check if there is no fault handler */
 		if (vm_no_fault) {
 			*object = cdev_pager_allocate(vm_private_data, OBJT_DEVICE,
 			    &linux_cdev_pager_ops[1], size, nprot, *offset,
 			    td->td_ucred);
 		} else {
 			*object = cdev_pager_allocate(vm_private_data, OBJT_MGTDEVICE,
 			    &linux_cdev_pager_ops[0], size, nprot, *offset,
 			    td->td_ucred);
 		}
 
 		/* check if allocating the VM object failed */
 		if (*object == NULL) {
 			if (error == 0) {
 				/* remove VM area struct from list */
 				linux_cdev_handle_remove(vmap);
 				/* free allocated VM area struct */
 				linux_cdev_handle_free(vmap);
 			}
 			return (EINVAL);
 		}
 	} else {
 		struct sglist *sg;
 
 		sg = sglist_alloc(1, M_WAITOK);
 		sglist_append_phys(sg,
 		    (vm_paddr_t)vmap->vm_pfn << PAGE_SHIFT, vmap->vm_len);
 
 		*object = vm_pager_allocate(OBJT_SG, sg, vmap->vm_len,
 		    nprot, 0, td->td_ucred);
 
 		linux_cdev_handle_free(vmap);
 
 		if (*object == NULL) {
 			sglist_free(sg);
 			return (EINVAL);
 		}
 	}
 
 	if (attr != VM_MEMATTR_DEFAULT) {
 		VM_OBJECT_WLOCK(*object);
 		vm_object_set_memattr(*object, attr);
 		VM_OBJECT_WUNLOCK(*object);
 	}
 	*offset = 0;
 	return (0);
 }
 
 struct cdevsw linuxcdevsw = {
 	.d_version = D_VERSION,
 	.d_fdopen = linux_dev_fdopen,
 	.d_name = "lkpidev",
 };
 
 static int
 linux_file_read(struct file *file, struct uio *uio, struct ucred *active_cred,
     int flags, struct thread *td)
 {
 	struct linux_file *filp;
 	const struct file_operations *fop;
 	struct linux_cdev *ldev;
 	ssize_t bytes;
 	int error;
 
 	error = 0;
 	filp = (struct linux_file *)file->f_data;
 	filp->f_flags = file->f_flag;
 	/* XXX no support for I/O vectors currently */
 	if (uio->uio_iovcnt != 1)
 		return (EOPNOTSUPP);
 	if (uio->uio_resid > DEVFS_IOSIZE_MAX)
 		return (EINVAL);
 	linux_set_current(td);
 	linux_get_fop(filp, &fop, &ldev);
 	if (fop->read != NULL) {
 		bytes = OPW(file, td, fop->read(filp,
 		    uio->uio_iov->iov_base,
 		    uio->uio_iov->iov_len, &uio->uio_offset));
 		if (bytes >= 0) {
 			uio->uio_iov->iov_base =
 			    ((uint8_t *)uio->uio_iov->iov_base) + bytes;
 			uio->uio_iov->iov_len -= bytes;
 			uio->uio_resid -= bytes;
 		} else {
 			error = linux_get_error(current, -bytes);
 		}
 	} else
 		error = ENXIO;
 
 	/* update kqfilter status, if any */
 	linux_file_kqfilter_poll(filp, LINUX_KQ_FLAG_HAS_READ);
 	linux_drop_fop(ldev);
 
 	return (error);
 }
 
 static int
 linux_file_write(struct file *file, struct uio *uio, struct ucred *active_cred,
     int flags, struct thread *td)
 {
 	struct linux_file *filp;
 	const struct file_operations *fop;
 	struct linux_cdev *ldev;
 	ssize_t bytes;
 	int error;
 
 	filp = (struct linux_file *)file->f_data;
 	filp->f_flags = file->f_flag;
 	/* XXX no support for I/O vectors currently */
 	if (uio->uio_iovcnt != 1)
 		return (EOPNOTSUPP);
 	if (uio->uio_resid > DEVFS_IOSIZE_MAX)
 		return (EINVAL);
 	linux_set_current(td);
 	linux_get_fop(filp, &fop, &ldev);
 	if (fop->write != NULL) {
 		bytes = OPW(file, td, fop->write(filp,
 		    uio->uio_iov->iov_base,
 		    uio->uio_iov->iov_len, &uio->uio_offset));
 		if (bytes >= 0) {
 			uio->uio_iov->iov_base =
 			    ((uint8_t *)uio->uio_iov->iov_base) + bytes;
 			uio->uio_iov->iov_len -= bytes;
 			uio->uio_resid -= bytes;
 			error = 0;
 		} else {
 			error = linux_get_error(current, -bytes);
 		}
 	} else
 		error = ENXIO;
 
 	/* update kqfilter status, if any */
 	linux_file_kqfilter_poll(filp, LINUX_KQ_FLAG_HAS_WRITE);
 
 	linux_drop_fop(ldev);
 
 	return (error);
 }
 
 static int
 linux_file_poll(struct file *file, int events, struct ucred *active_cred,
     struct thread *td)
 {
 	struct linux_file *filp;
 	const struct file_operations *fop;
 	struct linux_cdev *ldev;
 	int revents;
 
 	filp = (struct linux_file *)file->f_data;
 	filp->f_flags = file->f_flag;
 	linux_set_current(td);
 	linux_get_fop(filp, &fop, &ldev);
 	if (fop->poll != NULL) {
 		revents = OPW(file, td, fop->poll(filp,
 		    LINUX_POLL_TABLE_NORMAL)) & events;
 	} else {
 		revents = 0;
 	}
 	linux_drop_fop(ldev);
 	return (revents);
 }
 
 static int
 linux_file_close(struct file *file, struct thread *td)
 {
 	struct linux_file *filp;
 	int (*release)(struct inode *, struct linux_file *);
 	const struct file_operations *fop;
 	struct linux_cdev *ldev;
 	int error;
 
 	filp = (struct linux_file *)file->f_data;
 
 	KASSERT(file_count(filp) == 0,
 	    ("File refcount(%d) is not zero", file_count(filp)));
 
 	if (td == NULL)
 		td = curthread;
 
 	error = 0;
 	filp->f_flags = file->f_flag;
 	linux_set_current(td);
 	linux_poll_wait_dequeue(filp);
 	linux_get_fop(filp, &fop, &ldev);
 	/*
 	 * Always use the real release function, if any, to avoid
 	 * leaking device resources:
 	 */
 	release = filp->f_op->release;
 	if (release != NULL)
 		error = -OPW(file, td, release(filp->f_vnode, filp));
 	funsetown(&filp->f_sigio);
 	if (filp->f_vnode != NULL)
 		vdrop(filp->f_vnode);
 	linux_drop_fop(ldev);
 	if (filp->f_cdev != NULL)
 		linux_cdev_deref(filp->f_cdev);
 	kfree(filp);
 
 	return (error);
 }
 
 static int
 linux_file_ioctl(struct file *fp, u_long cmd, void *data, struct ucred *cred,
     struct thread *td)
 {
 	struct linux_file *filp;
 	const struct file_operations *fop;
 	struct linux_cdev *ldev;
 	struct fiodgname_arg *fgn;
 	const char *p;
 	int error, i;
 
 	error = 0;
 	filp = (struct linux_file *)fp->f_data;
 	filp->f_flags = fp->f_flag;
 	linux_get_fop(filp, &fop, &ldev);
 
 	linux_set_current(td);
 	switch (cmd) {
 	case FIONBIO:
 		break;
 	case FIOASYNC:
 		if (fop->fasync == NULL)
 			break;
 		error = -OPW(fp, td, fop->fasync(0, filp, fp->f_flag & FASYNC));
 		break;
 	case FIOSETOWN:
 		error = fsetown(*(int *)data, &filp->f_sigio);
 		if (error == 0) {
 			if (fop->fasync == NULL)
 				break;
 			error = -OPW(fp, td, fop->fasync(0, filp,
 			    fp->f_flag & FASYNC));
 		}
 		break;
 	case FIOGETOWN:
 		*(int *)data = fgetown(&filp->f_sigio);
 		break;
 	case FIODGNAME:
 #ifdef	COMPAT_FREEBSD32
 	case FIODGNAME_32:
 #endif
 		if (filp->f_cdev == NULL || filp->f_cdev->cdev == NULL) {
 			error = ENXIO;
 			break;
 		}
 		fgn = data;
 		p = devtoname(filp->f_cdev->cdev);
 		i = strlen(p) + 1;
 		if (i > fgn->len) {
 			error = EINVAL;
 			break;
 		}
 		error = copyout(p, fiodgname_buf_get_ptr(fgn, cmd), i);
 		break;
 	default:
 		error = linux_file_ioctl_sub(fp, filp, fop, cmd, data, td);
 		break;
 	}
 	linux_drop_fop(ldev);
 	return (error);
 }
 
 static int
 linux_file_mmap_sub(struct thread *td, vm_size_t objsize, vm_prot_t prot,
     vm_prot_t *maxprotp, int *flagsp, struct file *fp,
     vm_ooffset_t *foff, const struct file_operations *fop, vm_object_t *objp)
 {
 	/*
 	 * Character devices do not provide private mappings
 	 * of any kind:
 	 */
 	if ((*maxprotp & VM_PROT_WRITE) == 0 &&
 	    (prot & VM_PROT_WRITE) != 0)
 		return (EACCES);
 	if ((*flagsp & (MAP_PRIVATE | MAP_COPY)) != 0)
 		return (EINVAL);
 
 	return (linux_file_mmap_single(fp, fop, foff, objsize, objp,
 	    (int)prot, td));
 }
 
 static int
 linux_file_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size,
     vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff,
     struct thread *td)
 {
 	struct linux_file *filp;
 	const struct file_operations *fop;
 	struct linux_cdev *ldev;
 	struct mount *mp;
 	struct vnode *vp;
 	vm_object_t object;
 	vm_prot_t maxprot;
 	int error;
 
 	filp = (struct linux_file *)fp->f_data;
 
 	vp = filp->f_vnode;
 	if (vp == NULL)
 		return (EOPNOTSUPP);
 
 	/*
 	 * Ensure that file and memory protections are
 	 * compatible.
 	 */
 	mp = vp->v_mount;
 	if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) {
 		maxprot = VM_PROT_NONE;
 		if ((prot & VM_PROT_EXECUTE) != 0)
 			return (EACCES);
 	} else
 		maxprot = VM_PROT_EXECUTE;
 	if ((fp->f_flag & FREAD) != 0)
 		maxprot |= VM_PROT_READ;
 	else if ((prot & VM_PROT_READ) != 0)
 		return (EACCES);
 
 	/*
 	 * If we are sharing potential changes via MAP_SHARED and we
 	 * are trying to get write permission although we opened it
 	 * without asking for it, bail out.
 	 *
 	 * Note that most character devices always share mappings.
 	 *
 	 * Rely on linux_file_mmap_sub() to fail invalid MAP_PRIVATE
 	 * requests rather than doing it here.
 	 */
 	if ((flags & MAP_SHARED) != 0) {
 		if ((fp->f_flag & FWRITE) != 0)
 			maxprot |= VM_PROT_WRITE;
 		else if ((prot & VM_PROT_WRITE) != 0)
 			return (EACCES);
 	}
 	maxprot &= cap_maxprot;
 
 	linux_get_fop(filp, &fop, &ldev);
 	error = linux_file_mmap_sub(td, size, prot, &maxprot, &flags, fp,
 	    &foff, fop, &object);
 	if (error != 0)
 		goto out;
 
 	error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object,
 	    foff, FALSE, td);
 	if (error != 0)
 		vm_object_deallocate(object);
 out:
 	linux_drop_fop(ldev);
 	return (error);
 }
 
 static int
 linux_file_stat(struct file *fp, struct stat *sb, struct ucred *active_cred,
     struct thread *td)
 {
 	struct linux_file *filp;
 	struct vnode *vp;
 	int error;
 
 	filp = (struct linux_file *)fp->f_data;
 	if (filp->f_vnode == NULL)
 		return (EOPNOTSUPP);
 
 	vp = filp->f_vnode;
 
 	vn_lock(vp, LK_SHARED | LK_RETRY);
 	error = VOP_STAT(vp, sb, td->td_ucred, NOCRED, td);
 	VOP_UNLOCK(vp);
 
 	return (error);
 }
 
 static int
 linux_file_fill_kinfo(struct file *fp, struct kinfo_file *kif,
     struct filedesc *fdp)
 {
 	struct linux_file *filp;
 	struct vnode *vp;
 	int error;
 
 	filp = fp->f_data;
 	vp = filp->f_vnode;
 	if (vp == NULL) {
 		error = 0;
 		kif->kf_type = KF_TYPE_DEV;
 	} else {
 		vref(vp);
 		FILEDESC_SUNLOCK(fdp);
 		error = vn_fill_kinfo_vnode(vp, kif);
 		vrele(vp);
 		kif->kf_type = KF_TYPE_VNODE;
 		FILEDESC_SLOCK(fdp);
 	}
 	return (error);
 }
 
 unsigned int
 linux_iminor(struct inode *inode)
 {
 	struct linux_cdev *ldev;
 
 	if (inode == NULL || inode->v_rdev == NULL ||
 	    inode->v_rdev->si_devsw != &linuxcdevsw)
 		return (-1U);
 	ldev = inode->v_rdev->si_drv1;
 	if (ldev == NULL)
 		return (-1U);
 
 	return (minor(ldev->dev));
 }
 
 struct fileops linuxfileops = {
 	.fo_read = linux_file_read,
 	.fo_write = linux_file_write,
 	.fo_truncate = invfo_truncate,
 	.fo_kqfilter = linux_file_kqfilter,
 	.fo_stat = linux_file_stat,
 	.fo_fill_kinfo = linux_file_fill_kinfo,
 	.fo_poll = linux_file_poll,
 	.fo_close = linux_file_close,
 	.fo_ioctl = linux_file_ioctl,
 	.fo_mmap = linux_file_mmap,
 	.fo_chmod = invfo_chmod,
 	.fo_chown = invfo_chown,
 	.fo_sendfile = invfo_sendfile,
 	.fo_flags = DFLAG_PASSABLE,
 };
 
 /*
  * Hash of vmmap addresses.  This is infrequently accessed and does not
  * need to be particularly large.  This is done because we must store the
  * caller's idea of the map size to properly unmap.
  */
 struct vmmap {
 	LIST_ENTRY(vmmap)	vm_next;
 	void 			*vm_addr;
 	unsigned long		vm_size;
 };
 
 struct vmmaphd {
 	struct vmmap *lh_first;
 };
 #define	VMMAP_HASH_SIZE	64
 #define	VMMAP_HASH_MASK	(VMMAP_HASH_SIZE - 1)
 #define	VM_HASH(addr)	((uintptr_t)(addr) >> PAGE_SHIFT) & VMMAP_HASH_MASK
 static struct vmmaphd vmmaphead[VMMAP_HASH_SIZE];
 static struct mtx vmmaplock;
 
 static void
 vmmap_add(void *addr, unsigned long size)
 {
 	struct vmmap *vmmap;
 
 	vmmap = kmalloc(sizeof(*vmmap), GFP_KERNEL);
 	mtx_lock(&vmmaplock);
 	vmmap->vm_size = size;
 	vmmap->vm_addr = addr;
 	LIST_INSERT_HEAD(&vmmaphead[VM_HASH(addr)], vmmap, vm_next);
 	mtx_unlock(&vmmaplock);
 }
 
 static struct vmmap *
 vmmap_remove(void *addr)
 {
 	struct vmmap *vmmap;
 
 	mtx_lock(&vmmaplock);
 	LIST_FOREACH(vmmap, &vmmaphead[VM_HASH(addr)], vm_next)
 		if (vmmap->vm_addr == addr)
 			break;
 	if (vmmap)
 		LIST_REMOVE(vmmap, vm_next);
 	mtx_unlock(&vmmaplock);
 
 	return (vmmap);
 }
 
 #if defined(__i386__) || defined(__amd64__) || defined(__powerpc__) || defined(__aarch64__)
 void *
 _ioremap_attr(vm_paddr_t phys_addr, unsigned long size, int attr)
 {
 	void *addr;
 
 	addr = pmap_mapdev_attr(phys_addr, size, attr);
 	if (addr == NULL)
 		return (NULL);
 	vmmap_add(addr, size);
 
 	return (addr);
 }
 #endif
 
 void
 iounmap(void *addr)
 {
 	struct vmmap *vmmap;
 
 	vmmap = vmmap_remove(addr);
 	if (vmmap == NULL)
 		return;
 #if defined(__i386__) || defined(__amd64__) || defined(__powerpc__) || defined(__aarch64__)
 	pmap_unmapdev((vm_offset_t)addr, vmmap->vm_size);
 #endif
 	kfree(vmmap);
 }
 
 void *
 vmap(struct page **pages, unsigned int count, unsigned long flags, int prot)
 {
 	vm_offset_t off;
 	size_t size;
 
 	size = count * PAGE_SIZE;
 	off = kva_alloc(size);
 	if (off == 0)
 		return (NULL);
 	vmmap_add((void *)off, size);
 	pmap_qenter(off, pages, count);
 
 	return ((void *)off);
 }
 
 void
 vunmap(void *addr)
 {
 	struct vmmap *vmmap;
 
 	vmmap = vmmap_remove(addr);
 	if (vmmap == NULL)
 		return;
 	pmap_qremove((vm_offset_t)addr, vmmap->vm_size / PAGE_SIZE);
 	kva_free((vm_offset_t)addr, vmmap->vm_size);
 	kfree(vmmap);
 }
 
 static char *
 devm_kvasprintf(struct device *dev, gfp_t gfp, const char *fmt, va_list ap)
 {
 	unsigned int len;
 	char *p;
 	va_list aq;
 
 	va_copy(aq, ap);
 	len = vsnprintf(NULL, 0, fmt, aq);
 	va_end(aq);
 
 	if (dev != NULL)
 		p = devm_kmalloc(dev, len + 1, gfp);
 	else
 		p = kmalloc(len + 1, gfp);
 	if (p != NULL)
 		vsnprintf(p, len + 1, fmt, ap);
 
 	return (p);
 }
 
 char *
 kvasprintf(gfp_t gfp, const char *fmt, va_list ap)
 {
 
 	return (devm_kvasprintf(NULL, gfp, fmt, ap));
 }
 
 char *
 lkpi_devm_kasprintf(struct device *dev, gfp_t gfp, const char *fmt, ...)
 {
 	va_list ap;
 	char *p;
 
 	va_start(ap, fmt);
 	p = devm_kvasprintf(dev, gfp, fmt, ap);
 	va_end(ap);
 
 	return (p);
 }
 
 char *
 kasprintf(gfp_t gfp, const char *fmt, ...)
 {
 	va_list ap;
 	char *p;
 
 	va_start(ap, fmt);
 	p = kvasprintf(gfp, fmt, ap);
 	va_end(ap);
 
 	return (p);
 }
 
 static void
 linux_timer_callback_wrapper(void *context)
 {
 	struct timer_list *timer;
 
-	linux_set_current(curthread);
-
 	timer = context;
+
+	if (linux_set_current_flags(curthread, M_NOWAIT)) {
+		/* try again later */
+		callout_reset(&timer->callout, 1,
+		    &linux_timer_callback_wrapper, timer);
+		return;
+	}
+
 	timer->function(timer->data);
 }
 
 int
 mod_timer(struct timer_list *timer, int expires)
 {
 	int ret;
 
 	timer->expires = expires;
 	ret = callout_reset(&timer->callout,
 	    linux_timer_jiffies_until(expires),
 	    &linux_timer_callback_wrapper, timer);
 
 	MPASS(ret == 0 || ret == 1);
 
 	return (ret == 1);
 }
 
 void
 add_timer(struct timer_list *timer)
 {
 
 	callout_reset(&timer->callout,
 	    linux_timer_jiffies_until(timer->expires),
 	    &linux_timer_callback_wrapper, timer);
 }
 
 void
 add_timer_on(struct timer_list *timer, int cpu)
 {
 
 	callout_reset_on(&timer->callout,
 	    linux_timer_jiffies_until(timer->expires),
 	    &linux_timer_callback_wrapper, timer, cpu);
 }
 
 int
 del_timer(struct timer_list *timer)
 {
 
 	if (callout_stop(&(timer)->callout) == -1)
 		return (0);
 	return (1);
 }
 
 int
 del_timer_sync(struct timer_list *timer)
 {
 
 	if (callout_drain(&(timer)->callout) == -1)
 		return (0);
 	return (1);
 }
 
 /* greatest common divisor, Euclid equation */
 static uint64_t
 lkpi_gcd_64(uint64_t a, uint64_t b)
 {
 	uint64_t an;
 	uint64_t bn;
 
 	while (b != 0) {
 		an = b;
 		bn = a % b;
 		a = an;
 		b = bn;
 	}
 	return (a);
 }
 
 uint64_t lkpi_nsec2hz_rem;
 uint64_t lkpi_nsec2hz_div = 1000000000ULL;
 uint64_t lkpi_nsec2hz_max;
 
 uint64_t lkpi_usec2hz_rem;
 uint64_t lkpi_usec2hz_div = 1000000ULL;
 uint64_t lkpi_usec2hz_max;
 
 uint64_t lkpi_msec2hz_rem;
 uint64_t lkpi_msec2hz_div = 1000ULL;
 uint64_t lkpi_msec2hz_max;
 
 static void
 linux_timer_init(void *arg)
 {
 	uint64_t gcd;
 
 	/*
 	 * Compute an internal HZ value which can divide 2**32 to
 	 * avoid timer rounding problems when the tick value wraps
 	 * around 2**32:
 	 */
 	linux_timer_hz_mask = 1;
 	while (linux_timer_hz_mask < (unsigned long)hz)
 		linux_timer_hz_mask *= 2;
 	linux_timer_hz_mask--;
 
 	/* compute some internal constants */
 
 	lkpi_nsec2hz_rem = hz;
 	lkpi_usec2hz_rem = hz;
 	lkpi_msec2hz_rem = hz;
 
 	gcd = lkpi_gcd_64(lkpi_nsec2hz_rem, lkpi_nsec2hz_div);
 	lkpi_nsec2hz_rem /= gcd;
 	lkpi_nsec2hz_div /= gcd;
 	lkpi_nsec2hz_max = -1ULL / lkpi_nsec2hz_rem;
 
 	gcd = lkpi_gcd_64(lkpi_usec2hz_rem, lkpi_usec2hz_div);
 	lkpi_usec2hz_rem /= gcd;
 	lkpi_usec2hz_div /= gcd;
 	lkpi_usec2hz_max = -1ULL / lkpi_usec2hz_rem;
 
 	gcd = lkpi_gcd_64(lkpi_msec2hz_rem, lkpi_msec2hz_div);
 	lkpi_msec2hz_rem /= gcd;
 	lkpi_msec2hz_div /= gcd;
 	lkpi_msec2hz_max = -1ULL / lkpi_msec2hz_rem;
 }
 SYSINIT(linux_timer, SI_SUB_DRIVERS, SI_ORDER_FIRST, linux_timer_init, NULL);
 
 void
 linux_complete_common(struct completion *c, int all)
 {
 	int wakeup_swapper;
 
 	sleepq_lock(c);
 	if (all) {
 		c->done = UINT_MAX;
 		wakeup_swapper = sleepq_broadcast(c, SLEEPQ_SLEEP, 0, 0);
 	} else {
 		if (c->done != UINT_MAX)
 			c->done++;
 		wakeup_swapper = sleepq_signal(c, SLEEPQ_SLEEP, 0, 0);
 	}
 	sleepq_release(c);
 	if (wakeup_swapper)
 		kick_proc0();
 }
 
 /*
  * Indefinite wait for done != 0 with or without signals.
  */
 int
 linux_wait_for_common(struct completion *c, int flags)
 {
 	struct task_struct *task;
 	int error;
 
 	if (SCHEDULER_STOPPED())
 		return (0);
 
 	task = current;
 
 	if (flags != 0)
 		flags = SLEEPQ_INTERRUPTIBLE | SLEEPQ_SLEEP;
 	else
 		flags = SLEEPQ_SLEEP;
 	error = 0;
 	for (;;) {
 		sleepq_lock(c);
 		if (c->done)
 			break;
 		sleepq_add(c, NULL, "completion", flags, 0);
 		if (flags & SLEEPQ_INTERRUPTIBLE) {
 			DROP_GIANT();
 			error = -sleepq_wait_sig(c, 0);
 			PICKUP_GIANT();
 			if (error != 0) {
 				linux_schedule_save_interrupt_value(task, error);
 				error = -ERESTARTSYS;
 				goto intr;
 			}
 		} else {
 			DROP_GIANT();
 			sleepq_wait(c, 0);
 			PICKUP_GIANT();
 		}
 	}
 	if (c->done != UINT_MAX)
 		c->done--;
 	sleepq_release(c);
 
 intr:
 	return (error);
 }
 
 /*
  * Time limited wait for done != 0 with or without signals.
  */
 int
 linux_wait_for_timeout_common(struct completion *c, int timeout, int flags)
 {
 	struct task_struct *task;
 	int end = jiffies + timeout;
 	int error;
 
 	if (SCHEDULER_STOPPED())
 		return (0);
 
 	task = current;
 
 	if (flags != 0)
 		flags = SLEEPQ_INTERRUPTIBLE | SLEEPQ_SLEEP;
 	else
 		flags = SLEEPQ_SLEEP;
 
 	for (;;) {
 		sleepq_lock(c);
 		if (c->done)
 			break;
 		sleepq_add(c, NULL, "completion", flags, 0);
 		sleepq_set_timeout(c, linux_timer_jiffies_until(end));
 
 		DROP_GIANT();
 		if (flags & SLEEPQ_INTERRUPTIBLE)
 			error = -sleepq_timedwait_sig(c, 0);
 		else
 			error = -sleepq_timedwait(c, 0);
 		PICKUP_GIANT();
 
 		if (error != 0) {
 			/* check for timeout */
 			if (error == -EWOULDBLOCK) {
 				error = 0;	/* timeout */
 			} else {
 				/* signal happened */
 				linux_schedule_save_interrupt_value(task, error);
 				error = -ERESTARTSYS;
 			}
 			goto done;
 		}
 	}
 	if (c->done != UINT_MAX)
 		c->done--;
 	sleepq_release(c);
 
 	/* return how many jiffies are left */
 	error = linux_timer_jiffies_until(end);
 done:
 	return (error);
 }
 
 int
 linux_try_wait_for_completion(struct completion *c)
 {
 	int isdone;
 
 	sleepq_lock(c);
 	isdone = (c->done != 0);
 	if (c->done != 0 && c->done != UINT_MAX)
 		c->done--;
 	sleepq_release(c);
 	return (isdone);
 }
 
 int
 linux_completion_done(struct completion *c)
 {
 	int isdone;
 
 	sleepq_lock(c);
 	isdone = (c->done != 0);
 	sleepq_release(c);
 	return (isdone);
 }
 
 static void
 linux_cdev_deref(struct linux_cdev *ldev)
 {
 
 	if (refcount_release(&ldev->refs))
 		kfree(ldev);
 }
 
 static void
 linux_cdev_release(struct kobject *kobj)
 {
 	struct linux_cdev *cdev;
 	struct kobject *parent;
 
 	cdev = container_of(kobj, struct linux_cdev, kobj);
 	parent = kobj->parent;
 	linux_destroy_dev(cdev);
 	linux_cdev_deref(cdev);
 	kobject_put(parent);
 }
 
 static void
 linux_cdev_static_release(struct kobject *kobj)
 {
 	struct linux_cdev *cdev;
 	struct kobject *parent;
 
 	cdev = container_of(kobj, struct linux_cdev, kobj);
 	parent = kobj->parent;
 	linux_destroy_dev(cdev);
 	kobject_put(parent);
 }
 
 void
 linux_destroy_dev(struct linux_cdev *ldev)
 {
 
 	if (ldev->cdev == NULL)
 		return;
 
 	MPASS((ldev->siref & LDEV_SI_DTR) == 0);
 	atomic_set_int(&ldev->siref, LDEV_SI_DTR);
 	while ((atomic_load_int(&ldev->siref) & ~LDEV_SI_DTR) != 0)
 		pause("ldevdtr", hz / 4);
 
 	destroy_dev(ldev->cdev);
 	ldev->cdev = NULL;
 }
 
 const struct kobj_type linux_cdev_ktype = {
 	.release = linux_cdev_release,
 };
 
 const struct kobj_type linux_cdev_static_ktype = {
 	.release = linux_cdev_static_release,
 };
 
 static void
 linux_handle_ifnet_link_event(void *arg, struct ifnet *ifp, int linkstate)
 {
 	struct notifier_block *nb;
 
 	nb = arg;
 	if (linkstate == LINK_STATE_UP)
 		nb->notifier_call(nb, NETDEV_UP, ifp);
 	else
 		nb->notifier_call(nb, NETDEV_DOWN, ifp);
 }
 
 static void
 linux_handle_ifnet_arrival_event(void *arg, struct ifnet *ifp)
 {
 	struct notifier_block *nb;
 
 	nb = arg;
 	nb->notifier_call(nb, NETDEV_REGISTER, ifp);
 }
 
 static void
 linux_handle_ifnet_departure_event(void *arg, struct ifnet *ifp)
 {
 	struct notifier_block *nb;
 
 	nb = arg;
 	nb->notifier_call(nb, NETDEV_UNREGISTER, ifp);
 }
 
 static void
 linux_handle_iflladdr_event(void *arg, struct ifnet *ifp)
 {
 	struct notifier_block *nb;
 
 	nb = arg;
 	nb->notifier_call(nb, NETDEV_CHANGEADDR, ifp);
 }
 
 static void
 linux_handle_ifaddr_event(void *arg, struct ifnet *ifp)
 {
 	struct notifier_block *nb;
 
 	nb = arg;
 	nb->notifier_call(nb, NETDEV_CHANGEIFADDR, ifp);
 }
 
 int
 register_netdevice_notifier(struct notifier_block *nb)
 {
 
 	nb->tags[NETDEV_UP] = EVENTHANDLER_REGISTER(
 	    ifnet_link_event, linux_handle_ifnet_link_event, nb, 0);
 	nb->tags[NETDEV_REGISTER] = EVENTHANDLER_REGISTER(
 	    ifnet_arrival_event, linux_handle_ifnet_arrival_event, nb, 0);
 	nb->tags[NETDEV_UNREGISTER] = EVENTHANDLER_REGISTER(
 	    ifnet_departure_event, linux_handle_ifnet_departure_event, nb, 0);
 	nb->tags[NETDEV_CHANGEADDR] = EVENTHANDLER_REGISTER(
 	    iflladdr_event, linux_handle_iflladdr_event, nb, 0);
 
 	return (0);
 }
 
 int
 register_inetaddr_notifier(struct notifier_block *nb)
 {
 
 	nb->tags[NETDEV_CHANGEIFADDR] = EVENTHANDLER_REGISTER(
 	    ifaddr_event, linux_handle_ifaddr_event, nb, 0);
 	return (0);
 }
 
 int
 unregister_netdevice_notifier(struct notifier_block *nb)
 {
 
 	EVENTHANDLER_DEREGISTER(ifnet_link_event,
 	    nb->tags[NETDEV_UP]);
 	EVENTHANDLER_DEREGISTER(ifnet_arrival_event,
 	    nb->tags[NETDEV_REGISTER]);
 	EVENTHANDLER_DEREGISTER(ifnet_departure_event,
 	    nb->tags[NETDEV_UNREGISTER]);
 	EVENTHANDLER_DEREGISTER(iflladdr_event,
 	    nb->tags[NETDEV_CHANGEADDR]);
 
 	return (0);
 }
 
 int
 unregister_inetaddr_notifier(struct notifier_block *nb)
 {
 
 	EVENTHANDLER_DEREGISTER(ifaddr_event,
 	    nb->tags[NETDEV_CHANGEIFADDR]);
 
 	return (0);
 }
 
 struct list_sort_thunk {
 	int (*cmp)(void *, struct list_head *, struct list_head *);
 	void *priv;
 };
 
 static inline int
 linux_le_cmp(void *priv, const void *d1, const void *d2)
 {
 	struct list_head *le1, *le2;
 	struct list_sort_thunk *thunk;
 
 	thunk = priv;
 	le1 = *(__DECONST(struct list_head **, d1));
 	le2 = *(__DECONST(struct list_head **, d2));
 	return ((thunk->cmp)(thunk->priv, le1, le2));
 }
 
 void
 list_sort(void *priv, struct list_head *head, int (*cmp)(void *priv,
     struct list_head *a, struct list_head *b))
 {
 	struct list_sort_thunk thunk;
 	struct list_head **ar, *le;
 	size_t count, i;
 
 	count = 0;
 	list_for_each(le, head)
 		count++;
 	ar = malloc(sizeof(struct list_head *) * count, M_KMALLOC, M_WAITOK);
 	i = 0;
 	list_for_each(le, head)
 		ar[i++] = le;
 	thunk.cmp = cmp;
 	thunk.priv = priv;
 	qsort_r(ar, count, sizeof(struct list_head *), &thunk, linux_le_cmp);
 	INIT_LIST_HEAD(head);
 	for (i = 0; i < count; i++)
 		list_add_tail(ar[i], head);
 	free(ar, M_KMALLOC);
 }
 
 void
 linux_irq_handler(void *ent)
 {
 	struct irq_ent *irqe;
 
 	if (linux_set_current_flags(curthread, M_NOWAIT))
 		return;
 
 	irqe = ent;
 	irqe->handler(irqe->irq, irqe->arg);
 }
 
 #if defined(__i386__) || defined(__amd64__)
 int
 linux_wbinvd_on_all_cpus(void)
 {
 
 	pmap_invalidate_cache();
 	return (0);
 }
 #endif
 
 int
 linux_on_each_cpu(void callback(void *), void *data)
 {
 
 	smp_rendezvous(smp_no_rendezvous_barrier, callback,
 	    smp_no_rendezvous_barrier, data);
 	return (0);
 }
 
 int
 linux_in_atomic(void)
 {
 
 	return ((curthread->td_pflags & TDP_NOFAULTING) != 0);
 }
 
 struct linux_cdev *
 linux_find_cdev(const char *name, unsigned major, unsigned minor)
 {
 	dev_t dev = MKDEV(major, minor);
 	struct cdev *cdev;
 
 	dev_lock();
 	LIST_FOREACH(cdev, &linuxcdevsw.d_devs, si_list) {
 		struct linux_cdev *ldev = cdev->si_drv1;
 		if (ldev->dev == dev &&
 		    strcmp(kobject_name(&ldev->kobj), name) == 0) {
 			break;
 		}
 	}
 	dev_unlock();
 
 	return (cdev != NULL ? cdev->si_drv1 : NULL);
 }
 
 int
 __register_chrdev(unsigned int major, unsigned int baseminor,
     unsigned int count, const char *name,
     const struct file_operations *fops)
 {
 	struct linux_cdev *cdev;
 	int ret = 0;
 	int i;
 
 	for (i = baseminor; i < baseminor + count; i++) {
 		cdev = cdev_alloc();
 		cdev->ops = fops;
 		kobject_set_name(&cdev->kobj, name);
 
 		ret = cdev_add(cdev, makedev(major, i), 1);
 		if (ret != 0)
 			break;
 	}
 	return (ret);
 }
 
 int
 __register_chrdev_p(unsigned int major, unsigned int baseminor,
     unsigned int count, const char *name,
     const struct file_operations *fops, uid_t uid,
     gid_t gid, int mode)
 {
 	struct linux_cdev *cdev;
 	int ret = 0;
 	int i;
 
 	for (i = baseminor; i < baseminor + count; i++) {
 		cdev = cdev_alloc();
 		cdev->ops = fops;
 		kobject_set_name(&cdev->kobj, name);
 
 		ret = cdev_add_ext(cdev, makedev(major, i), uid, gid, mode);
 		if (ret != 0)
 			break;
 	}
 	return (ret);
 }
 
 void
 __unregister_chrdev(unsigned int major, unsigned int baseminor,
     unsigned int count, const char *name)
 {
 	struct linux_cdev *cdevp;
 	int i;
 
 	for (i = baseminor; i < baseminor + count; i++) {
 		cdevp = linux_find_cdev(name, major, i);
 		if (cdevp != NULL)
 			cdev_del(cdevp);
 	}
 }
 
 void
 linux_dump_stack(void)
 {
 #ifdef STACK
 	struct stack st;
 
 	stack_zero(&st);
 	stack_save(&st);
 	stack_print(&st);
 #endif
 }
 
 #if defined(__i386__) || defined(__amd64__)
 bool linux_cpu_has_clflush;
 #endif
 
 static void
 linux_compat_init(void *arg)
 {
 	struct sysctl_oid *rootoid;
 	int i;
 
 #if defined(__i386__) || defined(__amd64__)
 	linux_cpu_has_clflush = (cpu_feature & CPUID_CLFSH);
 #endif
 	rw_init(&linux_vma_lock, "lkpi-vma-lock");
 
 	rootoid = SYSCTL_ADD_ROOT_NODE(NULL,
 	    OID_AUTO, "sys", CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, "sys");
 	kobject_init(&linux_class_root, &linux_class_ktype);
 	kobject_set_name(&linux_class_root, "class");
 	linux_class_root.oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(rootoid),
 	    OID_AUTO, "class", CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, "class");
 	kobject_init(&linux_root_device.kobj, &linux_dev_ktype);
 	kobject_set_name(&linux_root_device.kobj, "device");
 	linux_root_device.kobj.oidp = SYSCTL_ADD_NODE(NULL,
 	    SYSCTL_CHILDREN(rootoid), OID_AUTO, "device",
 	    CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "device");
 	linux_root_device.bsddev = root_bus;
 	linux_class_misc.name = "misc";
 	class_register(&linux_class_misc);
 	INIT_LIST_HEAD(&pci_drivers);
 	INIT_LIST_HEAD(&pci_devices);
 	spin_lock_init(&pci_lock);
 	mtx_init(&vmmaplock, "IO Map lock", NULL, MTX_DEF);
 	for (i = 0; i < VMMAP_HASH_SIZE; i++)
 		LIST_INIT(&vmmaphead[i]);
 	init_waitqueue_head(&linux_bit_waitq);
 	init_waitqueue_head(&linux_var_waitq);
 }
 SYSINIT(linux_compat, SI_SUB_DRIVERS, SI_ORDER_SECOND, linux_compat_init, NULL);
 
 static void
 linux_compat_uninit(void *arg)
 {
 	linux_kobject_kfree_name(&linux_class_root);
 	linux_kobject_kfree_name(&linux_root_device.kobj);
 	linux_kobject_kfree_name(&linux_class_misc.kobj);
 
 	mtx_destroy(&vmmaplock);
 	spin_lock_destroy(&pci_lock);
 	rw_destroy(&linux_vma_lock);
 }
 SYSUNINIT(linux_compat, SI_SUB_DRIVERS, SI_ORDER_SECOND, linux_compat_uninit, NULL);
 
 /*
  * NOTE: Linux frequently uses "unsigned long" for pointer to integer
  * conversion and vice versa, where in FreeBSD "uintptr_t" would be
  * used. Assert these types have the same size, else some parts of the
  * LinuxKPI may not work like expected:
  */
 CTASSERT(sizeof(unsigned long) == sizeof(uintptr_t));